The Applicants' UK Patent Specification Nos. 2127658A and 2137860A disclose microwave ovens of this type. In these ovens, control of the cooking process depends upon monitoring the variation of hot air temperature with time. This can vary from individual oven to oven because of manufacturing tolerances and variations in characteristics of components. The invention aims to provide a microwave oven which follows a cooking sequence dependent upon values measured during cooking, so compensating for variations between individual ovens.